Muffle flue



July 13, 1937. w, AXE 2,087,215

MUFFLE FLUE Filed March 10, 1936 Patented July 13, 1937 sale MUFFLE FLUEApplication March 10, 1936, Serial No. 68,082

2 Claims.

The invention relates to kilns and furnaces, and more especially tunnelkilns, and with regard to its more specific features to a mufile fluetherefor.

One object of the invention is to provide a muffle flue construction ofhigh efliciency so far as heat transference is concerned and of areadily manufactured construction. Another object of the invention istoprovide a muflie flue assembled from plates which may be of greatdensity. An-

other object of the invention is to provide an inexpensive constructionfor a mufile flue. Other objects will be in part obvious or in partpointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, as will beexemplified in the structure to be hereinafter described, and the scopeof the application of which will be in.- dicated in the followingclaims.

In the accompanying drawing in which is shown one of many possibleembodiments of the invention,

Fig. 1 is a transverse sectional view of a tunnel kiln havingincorporated in it two muffle flues according to my invention;

Fig. 2 is a side. elevation of a plate for my mufile flue;

Fig. 3 is a longitudinal sectional view taken on the line 33 of Fig. 2;

Fig. 4 is a bottom View of the plate of Fig. 2;

Fig. 5 is an end view of the plate of Fig. 2;

Fig. 6 is a transverse sectional view taken on the line 6-6 of Fig. 2;

Fig. '7 is a transverse sectional view taken on the line l! of Fig. 2;

Fig. 8 is a side elevation of the T used to attach two plates togetherin constructing my muffle flue;

Fig. 9 is a cross sectional view taken on the line 9-9 of Fig. 8 andshowing two plates in position in the T;

Fig. 10 is a view similar to Fig. 9 but taken on the line Iii-l0 of Fig.8;

Fig. 11 is a bottom View of the T, looking along lines parallel toelements of a plate.

Referring now to Fig. 1, a tunnel kiln may comprise a floor 20, a pairof rails 2|, 2! forming a track for a car 22 having wheels 23, the car22 being located between massive supports 24, 24 formed of firebrick andproviding ledges 25, 25 whose surfaces are in a common horizontal planefor the support of the mufile flues 26, 26 of the invention. The warechamber 21 is bounded by side walls 28, 28 of firebrick, and an arch 29also of firebrick, and suitable seals 36, 38 comprising dependingmembers attached to the car 22 and extending into troughs 3|, 3! whichare filled with sand is preferably provided to insulate the ware chamber2? from the chamber 32 in which are the tracks 2i and the running gearof the car 22. The ware 33 is piled upon the car 22 which travels slowlythrough the kiln, the cross section of Fig. 1 being more or less typicalof the entire length of the kiln. Combustion gases are generated in anyknown or desired manner and passed along and through the triangularflues 26 of the invention, ultimately emerging and passing throughpassages to stacks, not shown. the flue of the: invention may beutilized in any desired type of tunnel kiln, the type briefly describedbeing illustrative.

Considering now the construction of the flues 26, I provide a number ofidentical plates 35.

Fig. 3 shows a longitudinal section of the plate 35 which is shown inelevation in Fig. 2; the section is uniform alongthe entire transverseextent of each plate 35 between the dotted lines shown in Fig. 2. Figs.5, 6 and 7 are end and transverse sectional views of the plate 35 andFigs. 2 to '7 inclusive quite definitely establish the shape andconfiguration of the plates. It will be seen that they are corrugatedand fur- .thermore that one plate can be matched to another plate tomake a corrugated wall of indefinite extent. Furthermore, they arebevelled as shown.

I provide T shaped unions 40, as shown in Figs. 8, 9, 10 and 11. Iprovide as many T members 40 as there are plates 35. Each T comprises atop portion l 5, two similar side portions 42, and a vertical portion53. The under side of the portions 42 has a corrugated boundary, asshown in Figs. 8 and 11. Plates 35 fit between portions 42 and 43 asfully illustrated in the several views, particularly Figs. 9 and 10.

Three plates 35 and three Ts 40 are assembled together in the mannershown in Fig. 1. A plate 35 is first laid flat with the bevelled edges45 uppermost, and two Ts GB are then moved into engaging position withthis plate, the bottom side of the portions t2 being horizontal, asshown. The parts may be readily put together and cement may be laid inthe unions. Two more plates are now inserted at 60 to each other and tothe first plate to complete the triangle. The top T 4| may be slippedinto position after the two side plates 35 are inserted in the twobottom Ts ll. The fit of the plates in the Tunnel kilns are alreadyknown and 1 Ts is preferably slightly loose so that a slight angularmotion of the plates: is permitted. This is in order to prevent breakageof the parts. The space left by this loose fit is filled with a suitablecement in order tightly to seal the unions.

' and I may then interlock full length plates 35 with these same Ts;This will leave one-half of the length of the plates 35 extending beyondthe TS, and I may then interlock these plates with additional fulllength Ts which will leave the Ts but half filled with plates. I maythen use full length plates which will then extend beyond these Ts, andso on, finishing up with half length plates 35. Thus the entirestructure will be rigidly locked together.

For the manufacture of the plates and also the Ts, I use any refractorygranular material, for example aluminum oxide, silicon carbide, magnesiaor any other suitable refractory substance. This may be bonded togetherwith ceramic bond and burned in a kiln, for example the'plates may bemanufactured in a kiln having flues which are the subject of theinvention.

The muffle flues of the invention may be mounted upon plates or bricks50 to raise them slightly from the ledges 25, and bricks 59 are spacedfrom each other along the length of the kiln so that air can find itsway under the fines 26. By reason of the fact that the amount of heattransmitted is proportional to the surface area to a considerableextent, there is more heat transmitted through my corrugated plates thanthrough plane surface plates. At the same time the corrugations and theconstruction described forms a. stronger plate than a plane surfaceplate of the same cross section. These two features cooperate, for byreason of the greater strength and greater heat conduction, I may embodythe structure in a plate thinner than would otherwise be used and thusstill further increase the conduction of heat without losing strength.Stating this in another manner, a certain minimum strength is required;this may be achieved according to the present construction A with a verythin plate which transmits more heat than would a thicker plate of thesame strength and even more heat than would a plate of the samethickness but, not corrugated.

The interlocking arrangement with the three Ts is such as to form a veryrigid structure and at the same time there is little danger of breakagein assembling owing to the fact that the plates can readily be pushedinto position in the Ts. Still another feature of the invention residesin the fact that a mixture of refractory granular material and bond canbe pressed in a mold to great density. The shapes of theqcorrugatedplates are such that no impediment is presented to molding with a moldthe bottom of which represents one of the bevelled edges: of the platesand the top of which represents the other bevelled edge thereof. Thispermits tamping the material in the mold to form an extremely tough andstrong plate. Furthermore, the Ts may also be effectively molded.

Another feature or" the invention resides in the fact that thetriangular muffle flues disperse heat through the ware chamber 2? so asto give an evenheating thereof. It will be noticed that the platesnearest the walls 28 radiate heat outwardly to the walls 28 which isreflected upwardly to the arch 29. At the same time the plates 35nearest the ware send heat directly onto the ware 33. A higher rate ofconvection will be achieved by reason of the fact that air is drawnunder the bottom plates 35. By the use of corrugated plates I also avoidtoo much concentration of radiated heat on one spot in the ware as itpasses through the kiln.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth is to be interpretedas illustrative and not in a limiting sense.

I claim:

1. In a muflle flue, three identical plates, three identical unionscoterminous with the plates along the length of the flue and T shaped incross section, said unions holding the plates together in the form of anequilateral triangle, each plate being corrugated with the corrugationsextending perpendicular to the length of the flue.

2. In a mufile flue three identical corrugated plates bevelled on theopposite edges of one side, said bevelling being done at the ends of thecorrugations, three identical junction pieces extending substantiallythe length of the plates and being T-shaped in cross section that is tosay having a central stem and top cross piece and two downwardlyextending sides to the cross piece at an angle of approximately 30 tothe cross piece, the bevelled ends of the plates abutting the centralstem of the T and the side pieces having corrugations matching theexterior of the plates, whereby the three plates are interlockedtogether in substantially gas tight condition, the corrugationsextending perpendicularly the length of the flue.

CHARLES W. SAXE.

